Eye fundus observing and photographing optical system

Abstract

An eye fundus observing and photographing optical system has an objective lens including a main positive lens component and at least one positive lens component provided at that side of the main positive lens component which is adjacent to an eye to be examined, and an illuminating optical system including an apertured mirror disposed obliquely with respect to the optical axis of the objective lens to supply an illuminating light to the fundus of the eye through the objective lens. The reflected image position of the opening portion of the apertured mirror by the lens surface of said at least one positive lens component which is adjacent to the eye is made substantially coincident with a first position whereat the reflected image of the opening portion of the apertured mirror by the lens surface of the main positive lens component which is adjacent to the eye is formed, and the reflected image position of the opening portion of the apertured mirror by the lens surface of said at least one positive lens component which is adjacent to the apertured mirror is made substantially coincident with a second position which is more adjacent to the eye than said first position.

I claim: 
     
       1. An eye fundus observing and photographing optical system comprising an objective lens including a biconvex main positive lens component and at least one positive lens component provided at that side of said main positive lens component which is adjacent to an eye to be examined, and an illuminating optical system including an apertured mirror disposed obliquely with respect to the optical axis of said objective lens to supply an illuminating light to the fundus of said eye through said objective lens, the reflected image position of the opening portion of said apertured mirror by the eye-side lens surface of said at least one positive lens component being substantially coincident with a first position whereat the reflected image of the opening portion of said apertured mirror by the eye-side lens surface of said biconvex main positive lens component is formed, and the reflected image position of the opening portion of said apertured mirror by the apertured mirror-side lens surface of said at least one positive lens component being substantially coincident with a second position whereat the reflected image of the opening portion of said apertured mirror by the apertured mirror-side lens surface of said biconvex main positive lens component is formed, said second position being more adjacent to said eye than said first position; said biconvex main positive lens component having in itself a first cemented surface having its convex surface facing said apertured mirror and a second cemented surface having its concave surface facing to said apertured mirror, said second cemented surface being disposed at the apertured mirror side of said first cemented surface, the reflected image position of the opening of said apertured mirror by said first cemented surface being substantially coincident with said second position, and the reflected image position of the opening portion of said apertured mirror by said second cemented surface being substantially coincident with said first position;   wherein when the distance from the vertex of the lens surface of said at least one positive lens component which is most adjacent to said eye to the vertex of the lens surface of said main positive lens component which is adjacent to said eye is d1 and the center thickness of said main positive lens component is d2 and when the vertex of the lens surface of said main positive lens component which is adjacent to said apertured mirror is the origin of the coordinates and the apertured mirror side is the positive direction, the distance P 1  to said first position and the distance P 2  to said second position satisfy the following conditions:   -1/3d.sub.2 ≦P.sub.1 <d.sub.2                       (I)       -(2d.sub.1 +d.sub.2)≦P.sub.2 <d.sub.1 /4-d.sub.2 ; and (II)     wherein numerical data are as follows:   FIRST EMBODIMENT     ______________________________________                                    
           d0 = 34.55                                                     
r1 = -119.036                                                             
           d.sub.1'  = 20.0                                               
                      n1 = 1.62041                                        
                                  ν1 = 60.3                            
r2* = -29.510*                                                            
           d.sub.2'  = 1.0                                                
r3 = 75.617                                                               
           d.sub.3'  = 18.0                                               
                      n2 = 1.62041                                        
                                  ν2 = 60.3                            
r30 = -117.082                                                            
           d.sub.4'  = 2.0                                                
                      n3 = 1.74000                                        
                                  ν3 = 28.2                            
r31 = 47.507                                                              
           d.sub.5'  = 25.0                                               
                      n4 = 1.69350                                        
                                  ν4 = 53.6                            
r4 = -179.690                                                             
           d.sub.6'  = 131.4                                              
 ##STR3##                                                                 
______________________________________                                    
       wherein r represents the curvature radius of each lens surface, d' represents the center thickness of and the air space between each lens, n represents the refractive index, ν represents Abbe number, and the added numerals represent the order from the eye to be examined, and wherein d0 represents the distance between the eye to be examined and the first lens surface (r 1 ), and r 30  and r 31  represent the curvature radii of the cemented surfaces in the biconvex main positive lens component.   
     
     
       2. An eye fundus observing and photographing optical system comprising an objective lens including a positive meniscus main lens component having its convex surface facing the eye-side and at least two positive lens components provided at that side of said main positive lens component which is adjacent to an eye to be examined, and an illuminating optical system including an apertured mirror disposed obliquely with respect to the optical axis of said objective lens to supply an illuminating light to the fundus of said eye through said objective lens, the center of curvature of the concave lens surface of said positive meniscus main positive lens component which is adjacent to said apertured mirror being substantially coincident with a position intersecting the optical axis of said apertured mirror, the reflected image positions of the opening portion of said apertured mirror by the eye-side lens surfaces of said respective two positive lens components being substantially coincident with a first position whereat the reflected image of the opening portion of said apertured mirror by the eye-side lens surface of said positive meniscus main lens component is formed, and the reflected image positions of the opening portion of said apertured mirror by the apertured mirror-side lens surfaces of said respective at least two positive lens components being substantially coincident with a second position which is more adjacent to said eye than said first position; said positive meniscus main lens component having in itself a cemented surface having its convex surface facing to said apertured mirror, the reflected image position of the opening of said apertured mirror by said cemented surface being substantially coincident with said first position; and   wherein, when the distance from the vertex of the lens surface of said at least two positive lens component which is most adjacent to said eye to the vertex of the lens surface of said positive meniscus main lens component which is adjacent to said eye is d 1  and the center thickness of said positive meniscus main lens component is d 2  and when the vertex of the lens surface of said positive meniscus main positive lens component which is adjacent to said apertured mirror is the origin of the coordinates and the apertured mirror side is the positive direction, the distance P 1  to said first position and the distance P 2  to said second position satisfy the following condition:   -1/3d.sub.2 ≦P.sub.1 <d.sub.2                       (I)       -(2d.sub.1 +d.sub.2)≦P.sub.2 <(d.sub.1 /4)-d.sub.2  (II)     wherein numerical data are as follows:   SECOND EMBODIMENT     ______________________________________                                    
            d0 = 32.58                                                    
r1* = -121.343*                                                           
            d'.sub.1 = 14.0                                               
                       n1 = 1.62041                                       
                                   ν1 = 60.3                           
r2 = -39.036                                                              
            d'.sub.2 = 0.5                                                
r3 = 135.880                                                              
            d'.sub.3 = 12.0                                               
                       n2 = 1.62041                                       
                                   ν2 = 60.3                           
r4 = -95.499                                                              
            d'.sub.4 = 0.5                                                
r5* = 42.301*                                                             
            d'.sub.5 = 40.0                                               
                       n3 = 1.62041                                       
                                   ν3 = 60.3                           
r51 = -34.450                                                             
            d'.sub.6 = 2.0                                                
                       n4 = 1.75520                                       
                                   ν4 = 27.5                           
r6 = 90.000 d'.sub.7 = 90.0                                               
 ##STR4##                                                                 
______________________________________                                    
       wherein r represents the curvature radius of each lens surface, d' represents the center thickness of and the air space between each lens, n represents the refractive index, ν represents Abbe number, and the added numerals represent the order from the eye to be examined, and wherein d0 represents the distance between the eye to be examined and the first lens surface (r 1 ), and r 51  represents the curvature radius of the cemented surface in the positive meniscus main lens component.